wildwestsydney

Ok so I think I have a failing MAF. 1984 euro LH. I have solved my oil leak which was at the top of the list, now to the questionable MAF. Symptoms: at about 1950 RPM thru 2300 the engine will start to buck. If I step on the gas it clears, this tells me the TPS is working because the LH should kick in with acceleration enrichments which would clear the bucking. One thing that leads me to doubt the MAF is I can not duplicate the problem in the driveway sitting in neutral. Would this be due to the fact that there is no load on the motor? I unplugged the MAF and started it to see if it would go to limp home I believe it did, the car ran awful I did not even take it for a drive. I do not want to start just replacing fairly expensive part just on a hunch so does anyone have a good way, other than swapping out a known good MAF, to diagnose a failing MAF?

Also when the engine starts to buck is the LH slipping in and out of limp home as it would be getting bad info from the MAF or is it just using the bad info and coming up with bad pulse width for the injectors.

Thanks

Sam

Stromius

I've had some odd stuff going too with idle and missing and I first cleaned the MAF with CRC MAF Cleaner and then also replaced my Temp II after it tested bad.

Mrmerlin

check the timing of the dizzys remove both caps and spin to TDC make sure both hash marks line up with the rotors.
From your description it sounds like a MAF I had mine rebuilt here in CO for 175.00 my 84 Euro runs great now and it would run rich and stumble and buck,
with the rebuilt it is smooth as glass

wildwestsydney

Ok thats what I am looking for. I have no problem replacing the MAF but I just wat to know i am goin to solve the problem.

John Speake

How many miles on the car ? Anything over 80k and the MAF is a strong possibility, once you have eliminated inlet leaks etc.

From what you describe I would estimate your car probably has in excess of 120K miles on it. Euro LH
16v are very sensitive to MAF ageing.

wildwestsydney

I took out the MAF today and cleaned it with some MAF cleaner just to see if it would make any difference. I think it definately got better not by leaps and bounds but better. I have two lines of thinking going on here I can get a rebuilt MAF from one of the big rennlist supliers, or I could go all out and convert to a megasquirt ECU which would use a MAP signal for the fuel algorithm. If I go the MS route I would have total control over all fuel use and if I wanted to control the ignition as well. The MS route would be a little cheaper, but then I would never beable to sell the car if I wanted to, I think an after market ECU would scare away most buyers. Note, I do not have any plans to sell the car. I have done a MS conversion to my dualsport motocycle so I am capable of doing the conversion.

Nine2Eight

Mr. Merlin:

Could you elaborate more on how to check the dizzy timing. Assume I know nothing- which is close to the truth. Then, if it is not correct, what do you do?? Thanks very much.

Joe Celeste - Seminole, FL
87 928 S4
64 356 SC

John Speake

You need to buy a 928 Workshop Manual on CD from Jim Moorehouse jim928(at)ptd.net

Mrmerlin

to check the twin Dizzy, First put the engine at TDC make sure its TDC for the #1 plug, then remove both of the caps, pay attention to where the ignition coil wires go if you swap them the car wont run, You may have to disconnect the coil wires depending on how much extra wire you have at the caps.
mark any wires that you disonnect.
With the caps removed from the tops of each dist. look and see where the rotors are pointing they should both be pointing to a hash mark in the dist housing , if one of them is off and the other is on then the dist housing must be removed and taken apart to realign the small dist belt it might be better to replace the belt instead of doing the R n Reposition.
There are detailed repair instructions in the WSM as John Speake has mentioned.

Nine2Eight

Mr. Merlin:

Thanks. I am very curious now and will want to look at mine. Question - How far off the hash mark(s) is considered out of time? (1/8", 1/4", ?? etc.) How much does it take to notice performance degradation?

JPC